The Mophie Juice Pack Plus can more than double the battery life of your iPhone 4/4S without taking away any features or functionality. The lightweight hard shell case features a shock-proof rubberized band and a simple toggle switch lets you change between standby and charging mode.
What Do Strava Employees Say:
"The Mophie Case got me all the way to Kalalau Beach and back, recording with Strava the entire time (http://app.strava.com/activities/39430095). My phone battery was still at 100% by the end of the day, even though my legs were at 0." -Charlotte W.